In Vitro Cytotoxicity Analysis of Bioceramic Root Canal Sealers on Human Gingival Fibroblast Cells

ABSTRACT@#This study evaluated the cytotoxicity of four bioceramic root canal sealers (bioceramic sealers): GuttaFlow Bioseal (GB), MTA Fillapex, CeraSeal Bioceramic root canal sealer (CS), and iRoot SP root canal sealer (iRSP). The viability of human gingival fibroblast (HGF) cells was used to evaluate the cytotoxicity of these bioceramic sealers. HGF cells were cultured and exposed to bioceramic sealer extracts for 24 hours, 48 hours and 72 hours at 37°C in an incubator humidified with 5% CO2. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide or MTT assay was conducted to determine cell viability at each incubation period and compared among all bioceramic sealers. The Kruskal-Wallis test revealed statistically significant differences between the positive control group and MTA Fillapex, MTA Fillapex and GB, and between GB and iRSP with p < 0.05. However, no statistical differences were found in cell viability for each material across all the incubation periods. GB was the least cytotoxic bioceramic sealer with cell viability exceeding 90% throughout the 72-hour incubation followed by CS, iRSP, and MTA Fillapex with non-cytotoxicity after 72-hour incubation, mild cytotoxicity after 72-hour incubation, and mild cytotoxicity after 72-hour incubation, respectively. However, iRSP showed moderate cytotoxicity, and MTA Fillapex was severely cytotoxic (< 30% cell viability) after 24-hour incubation.

Cell proliferation assessment of human gingival fibroblasts treated with Clinacanthus nutans using alamarBlue assay

@#Clinacanthus nutans (C. nutans), a well-known ethnopharmacological plant consumed for its medicinal purposes by Southeast Asian communities. C. nutans is said to possess antipyretic, inflammatory, antiedemic as well as analgesic properties and used traditionally in treating various skin ailments, Herpes infection, cancer and diabetes. The young leaves of this C. nutans are consumed in Malaysia for maintaining health. In this study, the proliferative activity of human gingival fibroblast cells (HGF-1, ATCC®CRL-2014™, USA) treated with the ethanol extract obtained from C. nutans leaves at three different concentrations (250, 125 and 62.5 µg/ml) was compared with the untreated cells using alamarBlue assay. The proliferative activity of HGF-1 using alamarBlue assay showed that the cells treated with 62.5 μg/ml of ethanolic extract of C. nutans leaves exhibited increased proliferation compared to the other groups and hence does not exhibit any cytotoxicity on HGF-1.

Effects of TiO2 NPs coating-titanium for fibroblast adhesion / Efectos del recubrimiento de NPs de TiO2 sobre placas de titanio para la adhesión de fibroblastos

The objective of this study was to determine the effects of coating nanoparticles of titanium dioxide (TiO2 NPs) and irradiation -UV on plates of titanium (Ti) for the adhesion and proliferation of human gingival fibroblasts (HGF). A total of 15 Ti plates were divided into three groups (n = 5); (i) control Ti, (ii) experimental: Ti+TiO2 NPs, (iii) experimental: Ti+TiO2 NPs+UV. The plates were analyzed with atomic force microscopy (AFM) and the roughness (Ra and Rmax) was determined. UV irradiation was performed for 20 min. HGF were subcultured in DMEM+10 % fetal bovine serum (FBS) at 37 °C with 5 % CO2. 2x106 cells/mL were inoculated on the plates and incubated for 1 h and washed with phosphate buffer saline (PBS). In the case of cell proliferation, cells were incubated for further 24 h more. Cell viability was determined with the MTT method, the formazan was dissolved with dimethylsulfoxide (DMSO) and analyzed at 540 nm. Experiments were performed of three independent experiments and data were analyzed by Kruskall-Wallis and multiple comparison of Mann-Whitney test. The surface topography of samples corresponded as follow: Ti (Ra= 0,492 µm y Rms= 0.640 µm), Ti+NPs TiO2, (Ra= 0.55 µm y Rms= 0.714 µm), respectively. The coating with TiO2 NPs significantly (p <0.05) increased the adhesion and proliferation of HGF compared with the group. The modification of Ti plates by coated with TiO2 NPs significantly increased adhesion and proliferation of HGF with the formation of a hydrophilic surface which favors the humectancy. This treatment may be reported here convenient to accelerate osseointegration of dental implants based titanium.

El objetivo fue determinar los efectos del recubrimiento con nanopartículas de dióxido de titanio (TiO2 NPs) e irradiación UV sobre placas de titanio (Ti) para la adhesión y proliferación de fibroblastos gingivales humanos (FGH). Un total de 15 placas de Ti se dividieron en tres grupos (n= 5); (i) control Ti, (ii) experimental Ti+NPs TiO2, (iii) experimental: Ti+NPs TiO2+UV. Las placas fueron analizadas en microscopía de fuerza atómica (MFA) y se determinó la rugosidad (Ra y Rmax). La irradiación con UV se realizó durante 20 min. FGH fueron subcultivados en DMEM+10 % de suero fetal bovino a 37 °C con 5 % de CO2. 2x106 células/mL fueron inoculadas sobre las placas e incubadas durante 1 h, se lavaron con solución salina de buffer fosfato. En el caso de la proliferación celular, las células se incubaron por 24 h más. La viabilidad celular se determinó con el método de MTT, el formazan fue disuelto con dimetilsulfoxido y se analizó a 540 nm. Los experimentos se realizaron a partir de tres experimentos independientes y los datos se analizaron por Kruskall-Wallis y por comparación múltiple de Mann-Whitney. La topografía de la superficie de las muestras correspondio de la siguiente manera: Ti (Ra= 0,492 µm y Rms= 0,640 µm), Ti+NPs TiO2, (Ra= 0,55 µm y Rms= 0,714 µm), respectivamente. El recubrimiento con NPs TiO2 aumentó significativamente la adhesión y proliferación de HGF en comparación con el grupo de Ti control (p <0,05). La modificación de la superficie de las placas de Ti recubiertas con NPs TiO2 aumentó significativamente la adhesión y proliferación de HGF con la formación de una superficie hidrófila que favorece la humectancia. Este tratamiento aquí informado tal vez sea un método conveniente para acelerar el proceso de la osteointegración de los implantes dentales a base de titanio.

The study of cytocompatibility of Co-Cr alloy and Ti alloy / 天津医药

Objective To investigate the cytocompatibility of the liching liquids of Co-Cr alloy and Ti alloy on human gingival fibroblasts (HGF). Methods The HGF were treated in vitro with leaching liquids of Co-Cr alloy and Ti alloy, respectively. The DMEM cell medium containing 10% fetal bovine serum was served as a negative control. The viability of HGF treated by two dental alloys were evaluated by means of MTT, and the contents of intracellular reduced glutathione (rGSH) were assayed by kits. The tumor necrosis factor-α(TNF-α) contents were determined in the culture supernatant by ELISA in two groups. The effects of these alloys on the expression of caspase-3 were examined by real time-PCR method. Results Compared with the control group, HGF treated with Co-Cr alloy leaching liquids showed a lower viability ( P ＜0.05), while Ti alloy leaching liquid promoted the proliferation of HGF. In Co-Cr alloy group, the rGSH content was significantly decreased (P＜0.05), while TNF-α content was significantly increased (P＜0.05) compared with control group. There were no significant differences in rGSH and TNF-α contents between the Ti alloy group and control group (P＞0.05). The expression of caspase-3 was significantly higher in Co-Cr alloy group than that of control group (P＜0.05), while there was no significant difference in the expression of caspase-3 between Ti alloy group and control group. Conclusion Results suggest that Co-Cr alloy possesses cytotoxicity, while there is better cell compatibility for Ti alloy.

Antimicrobial activity against periodontopathogenic bacteria, antioxidant and cytotoxic effects of various extracts from endemic Thermopsis turcica

Objective: To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan, Vural&Küçüködük against periodontopathogenic bacteria, its antioxidant activity and cytotoxic effect on various cancer cell lines. Methods: In vitro antimicrobial activities of ethanol, methanol, ethyl acetate (EtAc), n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Antioxidant properties of the extracts were evaluated by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and β-carotene bleaching methods. Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent. Additionally, cytotoxic activity of the extracts on androgen-insensitive prostate cancer, androgen-sensitive prostate cancer, chronic myelogenous leukemia and acute promyelocytic leukemia human cancer cell lines were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human gingival fibroblast cells were used as a control. Results: Our data showed that EtAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemcomitans (MIC: 1.562 mg/mL, MBC: 3.124 mg/mL) and Porphyromonas gingivalis (MIC: 0.781 mg/mL, MBC: 1.562 mg/mL). In antioxidant assays, EtAc extract exhibited also the highest radical scavenging activity [IC

Antimicrobial activity against periodontopathogenic bacteria, antioxidant and cytotoxic effects of various extracts from endemic Thermopsis turcica

Objective: To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan, Vural &Kü?ük?dük against periodontopathogenic bacteria, its antioxidant activity and cytotoxic effect on various cancer cell lines.Methods: In vitro antimicrobial activities of ethanol, methanol, ethyl acetate (EtAc), n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Antioxidant properties of the extracts were evaluated by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and β-carotene bleaching methods. Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent. Additionally, cytotoxic activity of the extracts on androgen-insensitive prostate cancer, androgen-sensitive prostate cancer, chronic myelogenous leukemia and acute promyelocytic leukemia human cancer cell lines were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human gingival fibroblast cells were used as a control.Results:Our data showed that EtAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemcomitans (MIC: 1.562 mg/mL, MBC: 3.124 mg/mL) and Porphyromonas gingivalis (MIC: 0.781 mg/mL, MBC: 1.562 mg/mL). In antioxidant assays, EtAc extract exhibited also the highest radical scavenging activity [IC50=(30.0±0.3) μg/mL] and the highest inhibition [(74.35±0.30)%] against lineloic acide oxidation. The amount of phenolic content of it was also the highest [(162.5±1.2) μg/mg gallic acid]. In cytotoxic assay, only ethanol [IC50=(80.00±1.21) μg/mL] and EtAc extract [IC50=(70.0±0.9) μg/mL] were toxic on acute promyelocytic leukemia cells at 20-100 μg/mL (P<0.05). However, no toxic effect was observed on human gingival fibroblast cells.Conclusions:According to our findings, owing to its antioxidant and cytotoxic potential, EtAc extract might include anticancer agents for acute promyelocytic leukemia.

Cellular viability and genetic expression of human gingival fibroblasts to zirconia with enamel matrix derivative (Emdogain(R))

PURPOSE: The objective of this study was to investigate the biologic effects of enamel matrix derivative (EMD) with different concentrations on cell viability and the genetic expression of human gingival fibroblasts (HGF) to zirconia surfaces. MATERIALS AND METHODS: Immortalized human gingival fibroblasts (HGF) were cultured (1) without EMD, (2) with EMD 25 microg/mL, and (3) with EMD 100 microg/mL on zirconia discs. MTT assay was performed to evaluate the cell proliferation activity and SEM was carried out to examine the cellular morphology and attachment. The mRNA expression of collagen type I, osteopontin, fibronectin, and TGF-beta1 was evaluated with the real-time polymerase chain reaction (RT-PCR). RESULTS: From MTT assay, HGF showed more proliferation in EMD 25 microg/mL group than control and EMD 100 microg/mL group (P<.05). HGFs showed more flattened cellular morphology on the experimental groups than on the control group after 4h culture and more cellular attachments were observed on EMD 25 microg/mL group and EMD 100 microg/mL group after 24h culture. After 48h of culture, cellular attachment was similar in all groups. The mRNA expression of type I collagen increased in a concentration dependent manner. The genetic expression of osteopontin, fibronectin, and TGF-beta1 was increased at EMD 100 microg/mL. However, the mRNA expression of proteins associated with cellular attachment was decreased at EMD 25 microg/mL. CONCLUSION: Through this short term culture of HGF on zirconium discs, we conclude that EMD affects the proliferation, attachment, and cell morphology of HGF cells. Also, EMD stimulates production of extracellular matrix collagen, osteopontin, and TGF-beta1 in high concentration levels. CLINICAL RELEVANCE: With the use of EMD, protective barrier between attached gingiva and transmucosal zirconia abutment may be enhanced leading to final esthetic results with implants.

Antimicrobial activity against periodontopathogenic bacteria, antioxidant and cytotoxic effects of various extracts from endemic Thermopsis turcica

<p><b>OBJECTIVE</b>To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan, Vural & Küçüködük against periodontopathogenic bacteria, its antioxidant activity and cytotoxic effect on various cancer cell lines.</p><p><b>METHODS</b>In vitro antimicrobial activities of ethanol, methanol, ethyl acetate (EtAc), n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria, Aggregatibacter actinomycetemcomitans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Antioxidant properties of the extracts were evaluated by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and β-carotene bleaching methods. Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent. Additionally, cytotoxic activity of the extracts on androgen-insensitive prostate cancer, androgen-sensitive prostate cancer, chronic myelogenous leukemia and acute promyelocytic leukemia human cancer cell lines were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Human gingival fibroblast cells were used as a control.</p><p><b>RESULTS</b>Our data showed that EtAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemcomitans (MIC: 1.562 mg/mL, MBC: 3.124 mg/mL) and Porphyromonas gingivalis (MIC: 0.781 mg/mL, MBC: 1.562 mg/mL). In antioxidant assays, EtAc extract exhibited also the highest radical scavenging activity [IC50=(30.0±0.3) µg/mL] and the highest inhibition [(74.35±0.30)%] against lineloic acide oxidation. The amount of phenolic content of it was also the highest [(162.5±1.2) µg/mg gallic acid]. In cytotoxic assay, only ethanol [IC50=(80.00±1.21) µg/mL] and EtAc extract [IC50=(70.0±0.9) µg/mL] were toxic on acute promyelocytic leukemia cells at 20-100 µg/mL (P<0.05). However, no toxic effect was observed on human gingival fibroblast cells.</p><p><b>CONCLUSIONS</b>According to our findings, owing to its antioxidant and cytotoxic potential, EtAc extract might include anticancer agents for acute promyelocytic leukemia.</p>

Effect of bamboo salt on human gingival fibroblasts / 대한구강보건학회지

OBJECTIVES: To evaluate the anti-inflammatory and cytotoxic activities of bamboo salt. METHODS: Cytotoxicity of bamboo salt and bay salt (0.01%, 0.1%, and 1%) was evaluated using MTT assay. In addition, secretion of the pro-inflammatory cytokines interleukin (IL)-1beta and IL-6 from human gingival fibroblasts (HGFs) was measured after application of 0.01% and 0.1% concentrations by using real-time polymerase chain reaction. RESULTS: Bamboo salt and bay salt at 1% concentration were cytotoxic to HGFs at 24 h; however, no such effect was observed at 0.01% or 0.1%. Bamboo salt showed a relatively low inhibitory effect. IL-1beta secretion was inhibited by a 0.1% solution of bamboo salt. IL-6 secretion was inhibited by both bamboo salt and bay salt at 0.1% concentration. CONCLUSIONS: The above results suggest that bamboo salt inhibits the release of IL-1beta and IL-6 from HGFs. Thus, bamboo salt may be a useful material for gingival inflammation.

Constituents Released from Streptococcus mutans Attenuate Arecoline-mediated Cytotoxicity in HGF Cells by Altering Intracellular Ca2+ Signaling

Streptococcus mutans (S. mutans) is a facultative anaerobic bacterium mainly found in the oral cavity and is known to contribute to tooth decay and gingivitis. Recent studies on intestinal microbiota have revealed that microorganisms forming a biofilm play important roles in maintaining tissue homeostasis through their own metabolism. However, the physiological roles of oral microorganisms such as S. mutans are still unclear. In our current study, we identified that constituents released from S. mutans (CR) reduce arecoline-mediated cytotoxicity without producing toxic effects themselves. Arecoline, as a major alkaloid of areca nut, is known to mediate cytotoxicity on oral epithelial cells and induces a sustained intracellular Ca2+ ([Ca2+]i) increase that is cytotoxic. The exposure of human gingival fibroblast (HGF) cells to CR not only inhibited the sustained [Ca2+]i increase but also the initial [Ca2+]i elevation. In contrast, CR had no effects on the gene regulation mediated by arecoline. These results demonstrate that S. mutans has physiological role in reducing cytotoxicity in HGF cells and may be considered a novel pharmaceutical candidate.

Jatropha curcas latex inhibits the release of collagenase by gingival fibroblast.

Folkloric use of J. curcas latex among others are to cure tooth pain, bleeding gum and as anti-inflammatory drug. Collagenase is a neutral protease released by activated macrophage and also by fibroblasts in small amounts. The aim of this study was to evaluate the effect of J. curcas latex on collagenase released by fibroblasts. Four doses of J. curcas latex from 37.5-300 g/ml were added to 3 human gingival primary fibroblast cell culture. After 1 to 4 days of incubation, collagenase in the supernatant was assayed with collagen. The degradation products were then separated by SDS-PAGE and the density of ¾ A bands were measured semi quantitatively by Adobe Photo computer program. Result showed that J. curcas latex decreased collagenase released by human gingival fibroblast, and increasing dose inhibits more. It may be concluded that the latex of J. curcas inhibits the release of collagenase by human gingival fibroblast.

Evaluation on cytotoxicity of propolis and calcium hydroxide / 重庆医科大学学报

Objective:To evaluate the cytotoxicity of propolis and calcium hydroxide for human gingival fibroblast.Methods:Human gingival fibroblast(HGF)was incubated in culture solution containing propolis or calcium hydroxide at different concentrations.The relative growth rates(RGR)were examined by method of MTT assay and cytotoxicity was classified by the five-class method.Then the results were statistically analysed.Results:The cytotoxicities of both 0.1% to 0.6% propolis and calcium hydroxide solutions at different concentration were all graded as first or second class.There was no statistical difference between them.Conclusion:Propolis and calcium hydroxide have weak cytotoxicity for HGF and they are all safe as local application for oral diseases.

Two colorimetric assays verify that calcium sulfate promotes proliferating activity of human gingival fibroblasts / 대한치과보철학회지

STATEMENT OF PROBLEM: The role of calcium sulfate in stimulating the growth of gingival soft tissue has been reported in few studies. Such a unique property of calcium sulfate could serve as a trouble-solving broker in compensating for the lack of soft tissues in various oral surgeries. PURPOSE: The purpose of this study was to compare the proliferating activities of human gingival fibroblasts seeded on various bone graft barrier materials of calcium sulfate, collagen, and polytetrafluorethylene (PTFE). MATERIAL AND METHODS: Two calcium sulfates (CAPSET(R) and CalForma(R), Lifecore Biomedical Inc., St. Paul, Minnesota, USA), a resorbable natural collagen (Bio-Gide(R), Geistlich Pharma Ag., Wolhusen, Switzerland), and a non-resorbable PTFE (TefGen-FD(R), Lifecore Biomedical Inc., St. Paul, Minnesota, USA) served as the human gingival fibroblasts'substrates and comprised the four experimental groups, whereas the untreated floors of culture plastics were used in the control group, in this study. Cells were trypsinized, seeded, and incubated for 48 h. The proliferating activities of fibroblasts were determined by XTT and SRB assay and absorbance (optical density, OD) was measured. One-way ANOVA was used to analyze the differences in the mean OD values between the groups of CAPSET, CalForma, Bio-Gide, TefGen, and the control (p<0.05). RESULTS: From the XTT assay, the mean OD value of the control group, the highest, was significantly greater than that of any of the four experimental groups followed by CalForma, CAPSET, TefGen, and Bio-Gide. Further, the mean OD value of CalForma, was significantly greater compared to that of Bio-Gide. From the SRB assay, Calforma showed the highest mean OD value, which was significantly greater than that of any other groups, followed by the control, CAPSET, Bio-Gide, and TefGen. The mean OD values of both the control and CAPSET were significantly greater compared to that of TefGen (p<0.05). CONCLUSION: Assessment of the viability and proliferation of cultured fibroblasts seeded and incubated for 48 h on various barrier-material substrates using XTT and SRB assay showed that calcium sulfate CalForma(R) promotes the proliferating activity of human gingival fibroblasts.

Profiling of genes in healthy hGF, aging hGF, healthy hPDLF and inflammatory hPDLF by DNA microarray / 대한치주과학회지

No abstract available.

Screening of genes differentially expressed in cultured human periodontal ligament cells and human gingival fibroblasts / 대한치주과학회지

Periodontal ligament(PDL) cells and human gingival fibroblasts(HGFs) play important roles in development, regeneration, normal function, and pathologic alteration. PDL cells and HGFs have the similarity related with general characteristics of fibroblast such as spindle shaped morphology, the presence of vimentin intermediate filament and the synthesis of interstitial collagens and fibronectin. There were many studies about the differences between PDL cells and HGFs, but they were not about whole gene level. In this study, we tried to explain the differences of gene expression profiles between PDL cells and HGFs, and the differences among three individuals by screening gene expression patterns of PDL cells and HGFs, using cDNA microarray. Although there were some variants among three experiments, a set of genes were consistentely and differentially expressed in one cell type. Among 3,063 genes, 49 genes were more highly expressed in PDL cells and 12 genes were more highly expressed in HGFs. The genes related with cell structure and motility were expressed more highly in PDL cells. These are cofilin 1, proteoglycan 1 secretory granule, collagen type I(alpha1), adducin gamma subunit, collagen type III(alpha1), fibronectin, lumican(keratan sulfate proteoglycan), and alpha-smooth muscle actin. Tissue inhibitor of metalloproteinase known as the enzyme controlling extracellular matrix with matrix metalloproteinase is more highly expressed in PDL cells, osteoprotegerin known as osteoclastogenesis inhibitory factor is more highly expressed in HGFs. We performed northern blot to verify cDNA microarray results on selected genes such as tissue inhibitor of metalloproteinase, fibronectin, osteoprogeterin. The result of northern blot analysis showed that each cell expressed the genes in similar pattern with cDNA microarray result. This result indicates that cDNA microarray is a reliable method in screening of gene expression profiles.

Triclosan Inhibition of Prostaglandin E2 Production in Human Gingival Fibroblast / 대한치주과학회지

The triclosan was shown to have anti-microbial and anti-inflammatory effect with inhibition of inflammatory mediators such as prostaglandin E2 (PGE2). The purpose of this study was to elucidate whether and how PGE2 could be inhibited by triclosan in human gingival fibroblast. Human gingival fibroblast-1 cells (ATCC CRL2014) were pre-treated for 1 hour with triclosan (0.001 microgram/ml~ 10 microgram/ml) and then stimulated with TNF-alpha(1.0 ng/ml). PGE2 synthesis was evaluated by ELISA and gene expression of COX-1 and COX-2 was evaluated by RT-PCR after TNF-alpha, triclosan, and NS-398 (COX-2 inhibitor, 5 micrometer) and/ or cycloheximide (protein synthesis inhibitor, 2 microgram/ml). Triclosan was cytotoxic to human gingival fibroblasts in the concentration higher than 1.0 microgram/ml for longer than 24 hours in tissue culture. The PGE2 synthesis was inhibited by triclosan in dose-dependent manner. Greater COX-2 mRNA suppression was observed with triclosan (0.1 microgram/ml) than with TNF-alphaalone, without change in COX-1 gene expression. Inhibitory effects of triclosan on PGE2 synthesis disappeared in presence of cycloheximide. This study suggests that triclosan inhibit prostaglandin E2 at the level of COX-2 gene regulation and require de novo protein synthesis.

Effects of Nicotine on the Expression of Cell Cycle Regulatory Proteins of Human Gingival Fibroblasts / 대한치주과학회지

Normal gingival fibroblasts functioning is fundamental for the maintenance of periodontal connective tissue as well as wound healing. Nicotine have been found to affect DNA synthesis and cell proliferation, which appear to depend on the type of cells. This in vitro study was done to determine the effects of nicotine, a major component of tobacco, on cell proliferation, viability, activity, cell cycle distribution, and expression of cell cycle regulatory proteins in human gingival fibroblasts. Nicotine has been tested for 2 days or 4 days in 5 different concentrations; 0.1 microgram/ml; 1 microgram/ml; 10 microgram/ml; 100 microgram/ml; 1000 microgram/ml. To assess cell proliferation and viability, viable and non-viable cells were counted by hemocytometer; to evaluate cellular activity, MTT assay was employed; to analyze cell cycle distribution, fluorescent propidium iodide-DNA complex were measured using fluorocytometer; to determine the expression of cell cycle regulatory proteins, western blot analysis was performed. After 2 days and 4 days incubation respectively, at concentrations of 1 microgram/ml - 1000 microgram/ml, nicotine significantly inhibited proliferation comparing to non-supplemented controls. The cell viability was significantly decreased after 2 days and 4 days at concentrations of 1 microgram/ml - 1000 microgram/ml and at 10 microgram/ml - 1000 microgram/ml respectively. After 2 days and 4 days, the cellular activity was significantly decreased at concentrations of 10 microgram/ml - 1000 microgram/ml. Treatment with 100 microgram/ml nicotine for 48 hours caused an increase in the proportion of G1-phase cells (from 46.41% to 53.46%) and a decrease in the proportion of S-phase cells (from 17.80% to 14.27%). The levels of cyclin D1 and CDK 4 proteins in nicotine-treated fibroblasts were lower than that of controls, whereas the levels of p16 and pRB were higher than that of controls. These results suggest that the decrease of cell proliferation and lengthened Gap phases (G1) by nicotine may due to the increased expression of p16 and pRB as well as decreased expression of cyclin D1 and CDK 4 in human gingival fibroblasts.